High affinity NY-ESO T cell receptors

ABSTRACT

The present invention provides T cell receptors (TCRs) having the property of binding to SLLMWITQC-HLA-A*0201, the SLLMWITQC SEQ ID NO:126 peptide being derived from the NY-ESO-1 protein which is expressed by a range of tumour cells. The TCRs have a K D  for the said peptide-HLA complex of less than or equal to 1 μM and/or have an off-rate (k off ) of 1×10 −3  S −1  or slower.

This application is a division of Ser. No. 12/854,691 filed on Aug. 11,2010, which is a division of Ser. No. 11/596,458 filed on Oct. 28, 2008as a national stage application of PCT/GB2005/001924 filed on May 18,2005. PCT/GB2005/001924 claims the benefit of GB 0411123.3 filed on May19, 2004 and GB 0419643.2 filed on Sep. 3, 2004.

This application incorporates by reference the contents of a 145 kb textfile created on Jul. 5, 2011 and named “sequencelisting.txt,” which isthe sequence listing for this application.

The present invention relates to T cell receptors (TCRs) having theproperty of binding to SLLMWITQC (SEQ ID NO:126)-HLA-A*0201 andcomprising at least one TCR α chain variable domain and/or at least oneTCR β chain variable domain CHARACTERISED IN THAT said TCR has a K_(off)for the said SLLMWITQC (SEQ ID NO:126)-HLA-A*0201 complex of less thanor equal to 1 μM and/or has an off-rate (k_(off)) for the SLLMWITQC (SEQID NO:126)-HLA-A*0201 complex of 1×10⁻³ S^(−l)or slower.

BACKGROUND TO THE INVENTION

The SLLMWITQC (SEQ ID NO:126) peptide is derived from the NY-ESO-Iprotein that is expressed by a range of tumours (Chen et al., (1997)PNAS USA 94 1914-1918). The Class I HLA molecules of these cancerouscells present peptides from this protein, including SLLMWITQC (SEQ IDNO:126). Therefore, the SLLMWITQC (SEQ ID NO:126)-HLA-A2 complexprovides a cancer marker that TCRs can target, for example for thepurpose of delivering cytotoxic or immuno-stimulatory agents to thecancer cells. However, for that purpose it would be desirable if the TCRhad a higher affinity and/or a slower off-rate for the peptide-HLAcomplex than native TCRs specific for that complex.

BRIEF DESCRIPTION OF THE INVENTION

This invention makes available for the first time TCRs having highaffinity (K_(D)) of the interaction less than or equal to 1 μM, and/or aslower off-rate (k_(off)) of 1×10⁻³ S⁻¹ or slower, for the SLLMWITQC(SEQ ID NO:126)-HLA-A*0201 complex. Such TCRs are useful, either aloneor associated with a therapeutic agent, for targeting cancer cellspresenting that complex.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides a T-cell receptor (TCR) having theproperty of binding to SLLMWITQC (SEQ ID NO:126)-HLA-A* 0201 andcomprising at least one TCR α chain variable domain and/or at least oneTCR β chain variable domain CHARACTERISED IN THAT said TCR has a K_(D)for the said SLLMWITQC (SEQ ID NO:126)-HLA-A*0201 complex of less thanor equal to 1 μM and/or has an off-rate (k_(off)) for the SLLMWITQC (SEQID NO:126)-HLA-A*0201 complex of 1×10⁻³ S⁻¹ or slower. The K_(D) and/or(k_(off)) measurement can be made by any of the known methods. Apreferred method is the Surface Plasmon Resonance (Biacore) method ofExample 5.

For comparison, the interaction of a disulfide-linked soluble variant ofthe native 1G4 TCR (see SEQ ID NO: 9 for TCR α chain and SEQ ID NO: 10for TCR β chain) and the SLLMWITQC-HLA-A*0201 complex has a KD ofapproximately 10 μM, an off-rate (k_(off)) of 1.28×10⁻¹ S⁻¹ and ahalf-life of 0.17 minutes as measured by the Biacore-base method ofExample 5.

The native 1G4 TCR specific for the SLLMWITQC (SEQ ID NO:126)-HLA-A*0201complex has the following Valpha chain and Vbeta chain gene usage:

-   -   Alpha chain—TRA V21    -   Beta chain:—TRBV 6.5

The native 1G4 TCR can be used as a template into which variousmutations that impart high affinity and/or a slow off-rate for theinteraction between TCRs of the invention and the SLLMWITQC (SEQ IDNO:126)-HLA-A*0201 complex can be introduced. Thus the inventionincludes TCRs which are mutated relative to the native 1 G4 TCR α chainvariable domain (see Figure Ia and SEQ ID No: 1) and/or β chain variabledomain (see Figure Ib and SEQ ID NO: 2) in at least one complementaritydetermining region (CDR) and/or variable domain framework regionthereof. It is also contemplated that other hypervariable regions in thevariable domains of the TCRs of the invention, such as the hypervariable4 (HV4) regions, may be mutated so as to produce a high affinity mutant.

Native TCRs exist in heterodimeric αβ or γδ forms. However, recombinantTCRs consisting of a single TCR α or TCR β chain have previously beenshown to bind to peptide MHC molecules.

In one embodiment the TCR of the invention comprise both an α chainvariable domain and an TCR β chain variable domain.

As will be obvious to those skilled in the art the mutation(s) in theTCR α chain sequence and/or TCR β chain sequence may be one or more ofsubstitution(s), deletion(s) or insertion(s). These mutations can becarried out using any appropriate method including, but not limited to,those based on polymerase chain reaction (PCR), restriction enzyme-basedcloning, or ligation independent cloning (LIC) procedures. These methodsare detailed in many of the standard molecular biology texts. Forfurther details regarding polymerase chain reaction (PCR) mutagenesisand restriction enzyme-based cloning see (Sambrook & Russell, (2001)Molecular Cloning—A Laboratory Manual (3^(rd) Ed.) CSHL Press) Furtherinformation on LIC procedures can be found in (Rashtchian, (1995) CurrOpin Biotechnol 6 (1): 30-6)

It should be noted that any αβ TCR that comprises similar Valpha andVbeta gene usage and therefore amino acid sequence to that of the 1G4TCR could make a convenient template TCR. It would then be possible tointroduce into the DNA encoding one or both of the variable domains ofthe template αβ TCR the changes required to produce the mutated highaffinity TCRs of the invention. As will be obvious to those skilled inthe art, the necessary mutations could be introduced by a number ofmethods, for example site-directed mutagenesis.

The TCRs of the invention include those in which one or more of the TCRalpha chain variable domain amino acids corresponding to those listedbelow are mutated relative to the amino acid occurring at thesepositions in the sequence provided for the native 1G4 TCR alpha chainvariable domain in FIG. 1 a and SEQ ID No: 1.

Unless stated to the contrary, the TCR amino acid sequences herein aregenerally provided including an N-terminal methionine (Met or M)residue. As will be known to those skilled in the art this residue maybe removed during the production of recombinant proteins. Furthermore,unless stated to the contrary, the soluble TCR and TCR variable domainsequences have been truncated at the N-terminus thereof. (Resulting inthe lose of the N-terminal “K” and “NA” in the TCR alpha and beta chainsequences respectively.). As will be obvious to those skilled in the artthese “missing” N-terminal TCR residues may be re-introduced into theTCRs of the present invention. As will also be obvious to those skilledin the art, it may be possible to truncate the sequences provided at theC-terminus and/or N-terminus thereof, by 1, 2, 3, 4, 5 or more residues,without substantially affecting the pMHC binding characteristics of theTCR, all such trivial variants are encompassed by the present invention.

As used herein the term “variable domain” is understood to encompass allamino acids of a given TCR which are not included within the constantdomain as encoded by the TRAC gene for TCR α chains and either the TRBC1or TRBC2 for TCR β chains. (T cell receptor Factsbook, (2001) LeFrancand LeFranc, Academic Press, ISBN 0-12-441352-8)

As is known to those skilled in the art, part of the diversity of theTCR repertoire is due to variations which occur in the amino acidencoded by the codon at the boundary between the variable domain, asdefined herein, and the constant domain. For example, the codon that ispresent at this boundary in the wild-type IG4 TCR sequence results inthe presence of the Tyrosine (Y) residue at the C-terminal of thevariable domain sequences herein. This Tyrosine replaces the N-terminalAsparagine (N) residue encoded by the TRAC gene shown in FIG. 8A.

Embodiments of the invention include mutated TCRs which comprisemutation of one or more of alpha chain variable domain amino acidscorresponding to: 20V, 51Q, 52S, 53S, 94P, 95T, 96S, 97G, 98G, 99S,100Y, 101I and 103T, for example the amino acids:

-   -   20A    -   51P/S/T or M    -   52P/F or G    -   53W/H or T    -   94H or A    -   95L/M/A/Q/Y/E/I/F/V/N/G/S/D or R    -   96L/T/Y/I/Q/V/E/X/A/W/R/G/H/D or K    -   97D/N/V/S/T or A    -   98P/H/S/T/W or A    -   99T/Y/D/H/V/N/E/G/Q/K/A/I or R    -   100F/M or D    -   101P/T/ or M    -   103A

The numbering used above is the same as that shown in FIG. 1 a and SEQID No: 1

Embodiments of the invention also include TCRs which comprise mutationof one or more of the TCR beta chain variable domain amino acidscorresponding to those listed below, are relative to the amino acidoccurring at these positions in the sequence provided for the native 1G4TCR alpha chain variable domain of the native 1G4 TCR beta chain in FIG.1 b and SEQ ID No: 2. The amino acids referred to which may be mutatedare: 18M, 50G, 51A, 52G, 53I, 55D, 56Q, 70T, 94Y, 95V and 97N, forexample:

-   -   18V    -   50S or A    -   51V or T    -   52Q    -   53T or M    -   55R    -   56R    -   70I    -   94N or F    -   95L    -   97G or D

The numbering used above is the same as that shown in FIG. 1 b and SEQID No: 2

Further preferred embodiments of the invention are provided by TCRscomprising one of the mutated alpha chain variable domain amino acidsequences shown in FIG. 6 (SEQ ID Nos: 11 to 83). Phenotypically silentvariants of such TCRs also form part of this invention.

Additional preferred embodiments of the invention are provided by TCRscomprising one of the mutated beta chain variable domain amino acidsequences shown in FIG. 7 or 13. (SEQ ID Nos: 84 to 99 or 117 to 121).Phenotypically silent variants of such TCRs also form part of thisinvention.

Native TCRs exist in heterodimeric αβ or γδ forms. However, recombinantTCRs consisting of αα or ββ homodimers have previously been shown tobind to peptide MHC molecules. Therefore, one embodiment of theinvention is provided by TCR αα or TCR ββ homodimers.

Further preferred embodiments are provided by TCRs of the inventioncomprising the alpha chain variable domain amino acid sequence and thebeta chain variable domain amino acid sequence combinations listedbelow, phenotypically silent variants of such TCRs also form part ofthis invention:

Alpha chain variable Beta chain variable domain sequence, domainsequence, SEQ ID NO: SEQ ID NO: 1 84 1 85 1 86 1 87 1 88 11 84 12 84 1285 12 90 11 85 11 86 11 92 11 93 13 86 14 84 14 85 15 84 15 85 16 84 1685 17 86 18 86 19 84 20 86 21 84 21 85 22 84 23 86 24 84 25 84 26 84 2784 28 84 29 84 30 84 31 84 32 84 33 84 20 86 34 86 35 89 36 89 37 89 3889 39 89 16 89 17 89 31 89 40 89 1 90 1 91 41 90 42 2 42 85 42 92 1 92 193 43 92 44 92 45 92 46 92 47 92 48 84 49 94 50 84 50 94 51 94 51 95 194 1 85 51 84 52 84 52 94 52 95 53 84 49 95 49 94 54 92 55 92 56 92 5792 58 92 59 92 60 92 61 92 62 92 63 92 64 92 65 92 66 92 67 92 68 92 6992 70 92 71 92 72 92 73 92 74 92 75 92 76 92 77 92 78 92 79 92 80 92 8192 82 92 83 92 11 96 11 97 11 98 11 99 1 89 50 117 49 117 50 118 49 11950 119 58 93 49 118 1 119 1 117 55 120 56 120 50 121 50 120 49 121 49120 48 118 53 95

Preferred embodiments provide a TCR of the invention comprising:

-   the alpha chain variable domain shown in the SEQ E) NO: 49 and the    beta chain variable domain shown in the SEQ ID NO: 94, or    phenotypically silent variants thereof.

In another preferred embodiment TCRs of the invention comprising thevariable domain combinations detailed above further comprise the alphachain constant region amino acid sequence shown in FIG. 8 a (SEQ ID NO:100) and one of the beta chain amino acid constant region sequencesshown in FIGS. 8 b and 8 c (SEQ ID NOs: 101 and 102) or phenotypicallysilent variants thereof.

As used herein the term “phenotypically silent variants” is understoodto refer to those TCRs which have a KD for the said SLLMWITQC (SEQ IDNO:126)-HLA-A*0201 complex of less than or equal to 1 μM and/or have anoff-rate (k_(off)) of 1×10⁻³ S⁻¹ or slower. For example, as is known tothose skilled in the art, it may be possible to produce TCRs thatincoporporate minor changes in the constant and/or variable domainsthereof compared to those detailed above without altering the affinityand/or off-rate for the interaction with the SLLMWITQC (SEQ IDNO:126)-HLA-A*0201 complex. Such trivial variants are included in thescope of this invention. Those TCRs in which one or more conservativesubstitutions have been made also form part of this invention.

In one broad aspect, the TCRs of the invention are in the form of eithersingle chain TCRs (scTCRs) or dimeric TCRs (dTCRs) as described in WO04/033685 and WO 03/020763.

A suitable scTCR form comprises a first segment constituted by an aminoacid sequence corresponding to a TCR α chain variable domain, a secondsegment constituted by an amino acid sequence corresponding to a TCR βchain variable domain sequence fused to the N terminus of an amino acidsequence corresponding to a TCR β chain constant domain extracellularsequence, and a linker sequence linking the C terminus of the firstsegment to the N terminus of the second segment.

Alternatively the first segment may be constituted by an amino acidsequence corresponding to a TCR β chain variable domain, the secondsegment may be constituted by an amino acid sequence corresponding to aTCR α chain variable domain sequence fused to the N terminus of an aminoacid sequence corresponding to a TCR α chain constant domainextracellular sequence

The above scTCRs may further comprise a disulfide bond between the firstand second chains, said disulfide bond being one which has no equivalentin native αβT cell receptors, and wherein the length of the linkersequence and the position of the disulfide bond being such that thevariable domain sequences of the first and second segments are mutuallyorientated substantially as in native αβ T cell receptors.

More specifically the first segment may be constituted by an amino acidsequence corresponding to a TCR α chain variable domain sequence fusedto the N terminus of an amino acid sequence corresponding to a TCR αchain constant domain extracellular sequence, the second segment may beconstituted by an amino acid sequence corresponding to a TCR β chainvariable domain fused to the N terminus of an amino acid sequencecorresponding to TCR β chain constant domain extracellular sequence, anda disulfide bond may be provided between the first and second chains,said disulfide bond being one which has no equivalent in native αβ Tcell receptors.

In the above scTCR forms, the linker sequence may link the C terminus ofthe first segment to the N terminus of the second segment, and may havethe formula -PGGG-(SGGGG)_(n)-P- wherein n is 5 or 6 and P is proline, Gis glycine and S is serine.

(SEQ ID NO: 103) -PGGG-SGGGGSGGGGSGGGGSGGGGSGGGG-P (SEQ ID NO: 104)-PGGG-SGGGGSGGGGSGGGGSGGGGSGGGGSGGGG-P

A suitable dTCR form of the TCRs of the present invention comprises afirst polypeptide wherein a sequence corresponding to a TCR α chainvariable domain sequence is fused to the N terminus of a sequencecorresponding to a TCR α chain constant domain extracellular sequence,and a second polypeptide wherein a sequence corresponding to a TCR βchain variable domain sequence fused to the N terminus a sequencecorresponding to a TCR β chain constant domain extracellular sequence,the first and second polypeptides being linked by a disulfide bond whichhas no equivalent in native αβ T cell receptors.

The first polypeptide may comprise a TCR α chain variable domainsequence is fused to the N terminus of a sequence corresponding to a TCRα chain constant domain extracellular sequence, and a second polypeptidewherein a sequence corresponding to a TCR β chain variable domainsequence is fused to the N terminus a sequence corresponding to a TCR βchain constant domain extracellular sequence, the first and secondpolypeptides being linked by a disulfide bond between cysteine residuessubstituted for Thr 48 of exon 1 of TRAC*01 and Ser 57 of exon 1 ofTRBC1*01 or TRBC2*01 or the non-human equivalent thereof. (“TRAC” etc.nomenclature herein as per T cell receptor Factsbook, (2001) LeFranc andLeFranc, Academic Press, ISBN 0-12-441352-8)

The dTCR or scTCR form of the TCRs of the invention may have amino acidsequences corresponding to human αβ TCR extracellular constant andvariable domain sequences, and a disulfide bond may link amino acidresidues of the said constant domain sequences, which disulfide bond hasno equivalent in native TCRs.

The disulfide bond is between cysteine residues corresponding to aminoacid residues whose β carbon atoms are less than 0.6 nm apart in nativeTCRs, for example between cysteine residues substituted for Thr 48 ofexon 1 of TRAC*01 and Ser 57 of exon 1 of TRBC1*01 or TRBC2*01 or thenon-human equivalent thereof. Other sites where cysteines can beintroduced to form the disulfide bond are the following residues in exon1 of TRAC*01 for the TCR α chain and TRBC1*01 or TRBC2*01 for the TCRchain:

Native β carbon TCR α chain TCR β chain separation (nm) Thr 45 Ser 770.533 Tyr 10 Ser 17 0.359 Thr 45 Asp 59 0.560 Ser 15 Glu 15 0.59

In addition to the non-native disulfide bond referred to above, the dTCRor scTCR form of the TCRs of the invention may include a disulfide bondbetween residues corresponding to those linked by a disulfide bond innative TCRs.

The dTCR or scTCR form of the TCRs of the invention preferably does notcontain a sequence corresponding to transmembrane or cytoplasmicsequences of native TCRs.

Preferred embodiments of the invention provide a soluble TCR consistingof:

-   the alpha chain amino acid sequence of SEQ ID NO: 122 and beta chain    amino acid sequence SEQ ID NO: 123:-   the alpha chain amino acid sequence of SEQ ID NO: 122 and beta chain    amino acid sequence SEQ ID NO: 124;-   SEQ ID NOs: 122, 123 and 124 have been provided in a form which    includes the N-terminal methionine (M) and the N-terminal “K” and    “NA” in the TCR alpha and beta chain sequences respectively.    PEGylated TCR Monomers

In one particular embodiment a TCR of the invention is associated withat least one polyalkylene glycol chain(s). This association may be causein a number of ways known to those skilled in the art. In a preferredembodiment the polyalkylene chain(s) is/are covalently linked to theTCR. In a further embodiment the polyethylene glycol chains of thepresent aspect of the invention comprise at least two polyethylenerepeating units.

Multivalent TCR Complexes

One aspect of the invention provides a multivalent TCR complexcomprising at least two TCRs of the invention. In one embodiment of thisaspect, at least two TCR molecules are linked via linker moieties toform multivalent complexes. Preferably the complexes are water soluble,so the linker moiety should be selected accordingly. Furthermore, it ispreferable that the linker moiety should be capable of attachment todefined positions on the TCR molecules, so that the structural diversityof the complexes formed is minimised. One embodiment of the presentaspect is provided by a TCR complex of the invention wherein the polymerchain or peptidic linker sequence extends between amino acid residues ofeach TCR which are not located in a variable region sequence of the TCR.

Since the complexes of the invention may be for use in medicine, thelinker moieties should be chosen with due regard to their pharmaceuticalsuitability, for example their immunogenicity.

Examples of linker moieties which fulfil the above desirable criteriaare known in the art, for example the art of linking antibody fragments.

There are two classes of linker that are preferred for use in theproduction of multivalent TCR molecules of the present invention. A TCRcomplex of the invention in which the TCRs are linked by a polyalkyleneglycol chain provides one embodiment of the present aspect.

The first are hydrophilic polymers such as polyalkylene glycols. Themost commonly used of this class are based on polyethylene glycol orPEG, the structure of which is shown below.HOCH₂CH₂O (CH₂CH₂O)_(n)—CH₂CH₂OH

Wherein n is greater than two. However, others are based on othersuitable, optionally substituted, polyalkylene glycols includepolypropylene glycol, and copolymers of ethylene glycol and propyleneglycol.

Such polymers may be used to treat or conjugate therapeutic agents,particularly polypeptide or protein therapeutics, to achieve beneficialchanges to the PK profile of the therapeutic, for example reduced renalclearance, improved plasma half-life, reduced immunogenicity, andimproved solubility. Such improvements in the PK profile of thePEG-therapeutic conjugate are believe to result from the PEG molecule ormolecules forming a ‘shell’ around the therapeutic which stericallyhinders the reaction with the immune system and reduces proteolyticdegradation. (Casey et al, (2000) Tumor Targetting 4 235-244) The sizeof the hydrophilic polymer used my in particular be selected on thebasis of the intended therapeutic use of the TCR complex. Thus forexample, where the product is intended to leave the circulation andpenetrate tissue, for example for use in the treatment of a tumour, itmay be advantageous to use low molecular weight polymers in the order of5 KDa. There are numerous review papers and books that detail the use ofPEG and similar molecules in pharmaceutical formulations. For example,see Harris (1992) Polyethylene Glycol Chemistry—

Biotechnical and Biomedical Applications, Plenum, New York, N.Y. orHarris & Zalipsky (1997) Chemistry and Biological Applications ofPolyethylene Glycol ACS Books, Washington, D.C.

The polymer used can have a linear or branched conformation. BranchedPEG molecules, or derivatives thereof, can be induced by the addition ofbranching moieties including glycerol and glycerol oligomers,pentaerythritol, sorbitol and lysine.

Usually, the polymer will have a chemically reactive group or groups inits structure, for example at one or both termini, and/or on branchesfrom the backbone, to enable the polymer to link to target sites in theTCR. This chemically reactive group or groups may be attached directlyto the hydrophilic polymer, or there may be a spacer group/moietybetween the hydrophilic polymer and the reactive chemistry as shownbelow:

-   -   Reactive chemistry-Hydrophilic polymer-Reactive chemistry    -   Reactive chemistry-Spacer-Hydrophilic polymer-Spacer-Reactive        chemistry

The spacer used in the formation of constructs of the type outlinedabove may be any organic moiety that is a non-reactive, chemicallystable, chain, Such spacers include, by are not limited to thefollowing:—(CH₂)_(n)— wherein n=2 to 5—(CH₂)₃NHCO(CH₂)₂

A TCR complex of the invention in which a divalent alkylene spacerradical is located between the polyalkylene glycol chain and its pointof attachment to a TCR of the complex provides a further embodiment ofthe present aspect.

A TCR complex of the invention in which the polyalkylene glycol chaincomprises at least two polyethylene glycol repeating units provides afurther embodiment of the present aspect.

There are a number of commercial suppliers of hydrophilic polymerslinked, directly or via a spacer, to reactive chemistries that may be ofuse in the present invention. These suppliers include NektarTherapeutics (CA, USA), NOF Corporation (Japan), Sunbio (South Korea)and Enzon Pharmaceuticals (NJ, USA).

Commercially available hydrophilic polymers linked, directly or via aspacer, to reactive chemistries that may be of use in the presentinvention include, but are not limited to, the following:

PEG linker Catalogue Description Source of PEG Number TCR Monomerattachment 5K linear (Maleimide) Nektar 2D2MOHO1 20K linear (Maleimide)Nektar 2D2MOPO1 20K linear (Maleimide) NOF Corporation SUNBRIGHTME-200MA 20K branched (Maleimide) NOF Corporation SUNBRIGHT GL2-200MA30K linear (Maleimide) NOF Corporation SUNBRIGHT ME-300MA 40K branchedPEG (Maleimide) Nektar 2D3XOTO1 5K-NP linear (for Lys attachment) NOFCorporation SUNBRIGHT MENP-50H 10K-NP linear (for Lys attachment) NOFCorporation SUNBRIGHT MENP-10T 20K-NP linear (for Lys attachment) NOFCorporation SUNBRIGHT MENP-20T TCR dimer linkers 3.4K linear (Maleimide)Nektar 2D2DOFO2 5K forked (Maleimide) Nektar 2D2DOHOF 10K linear (withorthopyridyl ds- Sunbio linkers in place of Maleimide) 20K forked(Maleimide) Nektar 2D2DOPOF 20K linear (Maleimide) NOF Corporation 40Kforked (Maleimide) Nektar 2D3XOTOF Higher order TCR multimers 15K, 3arms, Mal₃ (for trimer) Nektar OJOONO3 20K, 4 arms, Mal₄ (for tetramer)Nektar OJOOPO4 40K, 8 arms, Mal₈ (for octamer) Nektar OJOOTO8

A wide variety of coupling chemistries can be used to couple polymermolecules to protein and peptide therapeutics. The choice of the mostappropriate coupling chemistry is largely dependant on the desiredcoupling site. For example, the following coupling chemistries have beenused attached to one or more of the termini of PEG molecules (Source:Nektar Molecular Engineering Catalogue 2003):

-   -   N-maleimide    -   Vinyl sulfone    -   Benzotriazole carbonate    -   Succinimidyl proprionate    -   Succinimidyl butanoate    -   Thio-ester    -   Acetaldehydes    -   Acrylates    -   Biotin    -   Primary amines

As stated above non-PEG based polymers also provide suitable linkers formultimerising the TCRs of the present invention. For example, moietiescontaining maleimide termini linked by aliphatic chains such as BMH andBMOE (Pierce, products Nos. 22330 and 22323) can be used.

Peptidic linkers are the other class of TCR linkers. These linkers arecomprised of chains of amino acids, and function to produce simplelinkers or multimerisation domains onto which TCR molecules can beattached. The biotin/streptavidin system has previously been used toproduce TCR tetramers (see WO/99/60119) for in-vitro binding studies.However, stepavidin is a microbially-derived polypeptide and as such notideally suited to use in a therapeutic.

A TCR complex of the invention in which the TCRs are linked by apeptidic linker derived from a human multimerisation domain provides afurther embodiment of the present aspect.

There are a number of human proteins that contain a multimerisationdomain that could be used in the production of multivalent TCRcomplexes. For example the tetramerisation domain of p53 which has beenutilised to produce tetramers of scFv antibody fragments which exhibitedincreased serum persistence and significantly reduced off-rate comparedto the monomeric scFV fragment. (Willuda et al. (2001) J. Biol. Chem.276 (17) 14385-14392) Haemoglobin also has a tetramerisation domain thatcould potentially be used for this kind of application.

A multivalent TCR complex of the invention comprising at least two TCRsprovides a final embodiment of this aspect, wherein at least one of saidTCRs is associated with a therapeutic agent.

In one aspect a TCR (or multivalent complex thereof) of the presentinvention may alternatively or additionally comprise a reactive cysteineat the C-terminal or N-terminal of the alpha or beta chains thereof.

Diagnostic and Therapeutic Use

In one aspect the TCR of the invention may be associated with atherapeutic agent or detectable moiety. For example, said therapeuticagent or detectable moiety may be covalently linked to the TCR.

In one embodiment of the invention said therapeutic agent or detectablemoiety is covalently linked to the C-terminus of one or both TCR chains.

In one aspect the TCR of the invention may be associated with atherapeutic agent or detectable moiety. For example, said therapeuticagent or detectable moiety may be covalently linked to the TCR.

In one embodiment of the invention said therapeutic agent or detectablemoiety is covalently linked to the C-terminus of one or both TCR chains.In one aspect the scTCR or one or both of the dTCR chains of TCRs of thepresent invention may be labelled with an detectable moiety, for examplea label that is suitable for diagnostic purposes. Such labelled TCRs areuseful in a method for detecting a SLLMWITQC (SEQ ID NO:126)-HLA-A*0201complex which method comprises contacting the TCR ligand with a TCR (ora multimeric high affinity TCR complex) which is specific for the TCRligand; and detecting binding to the TCR ligand. In tetrameric TCRcomplexes formed for example, using biotinylated heterodimers,fluorescent streptavidin can be used to provide a detectable label. Sucha fluorescently-labelled TCR tetramer is suitable for use in FACSanalysis, for example to detect antigen presenting cells carrying theSLLMWITQC (SEQ ID NO:126)-HLA-A*0201 complex for which these highaffinity TCRs are specific.

Another manner in which the soluble TCRs of the present invention may bedetected is by the use of TCR-specific antibodies, in particularmonoclonal antibodies. There are many commercially available anti-TCRantibodies, such as αF1 and βF1, which recognise the constant domains ofthe α and β chains, respectively.

In a further aspect a TCR (or multivalent complex thereof) of thepresent invention may alternatively or additionally be associated with(e.g. covalently or otherwise linked to) a therapeutic agent which maybe, for example, a toxic moiety for use in cell killing, or an immuneeffector molecule such as an interleukin or a cytokine. A multivalentTCR complex of the invention may have enhanced binding capability for aTCR ligand compared to a non-multimeric wild-type or T cell receptorheterodimer of the invention. Thus, the multivalent TCR complexesaccording to the invention are particularly useful for tracking ortargeting cells presenting particular antigens in vitro or in vivo, andare also useful as intermediates for the production of furthermultivalent TCR complexes having such uses. These TCRs or multivalentTCR complexes may therefore be provided in a pharmaceutically acceptableformulation for use in vivo.

The invention also provides a method for delivering a therapeutic agentto a target cell, which method comprises contacting potential targetcells with a TCR or multivalent TCR complex in accordance with theinvention under conditions to allow attachment of the TCR or multivalentTCR complex to the target cell, said TCR or multivalent TCR complexbeing specific for the SLLMWITQC (SEQ ID NO:126)-HLA-A* 0201 complex andhaving the therapeutic agent associated therewith.

In particular, the soluble TCR or multivalent TCR complex of the presentinvention can be used to deliver therapeutic agents to the location ofcells presenting a particular antigen. This would be useful in manysituations and, in particular, against tumours. A therapeutic agentcould be delivered such that it would exercise its effect locally butnot only on the cell it binds to. Thus, one particular strategyenvisages anti-tumour molecules linked to TCRs or multivalent TCRcomplexes according to the invention specific for tumour antigens.

Many therapeutic agents could be employed for this use, for instanceradioactive compounds, enzymes (perforin for example) orchemotherapeutic agents (cis-platin for example). To ensure that toxiceffects are exercised in the desired location the toxin could be insidea liposome linked to streptavidin so that the compound is releasedslowly. This will prevent damaging effects during the transport in thebody and ensure that the toxin has maximum effect after binding of theTCR to the relevant antigen presenting cells.

Other suitable therapeutic agents include:

-   -   small molecule cytotoxic agents, i.e. compounds with the ability        to kill mammalian cells having a molecular weight of less than        700 daltons. Such compounds could also contain toxic metals        capable of having a cytotoxic effect. Furthermore, it is to be        understood that these small molecule cytotoxic agents also        include pro-drugs, i.e. compounds that decay or are converted        under physiological conditions to release cytotoxic agents.        Examples of such agents include cis-platin, maytansine        derivatives, rachelmycin, calicheamicin, docetaxel, etoposide,        gemcitabine, ifosfamide, irinotecan, melphalan, mitoxantrone,        sorfimer sodiumphotofrin II, temozolmide, topotecan, trimetreate        glucuronate, auristatin E vincristine and doxorubicin;    -   peptide cytotoxins, i.e. proteins or fragments thereof with the        ability to kill mammalian cells. Including but not limited to,        ricin, diphtheria toxin, pseudomonas bacterial exotoxin A,        DNAase and RNAase;    -   radio-nuclides, i.e. unstable isotopes of elements which decay        with the concurrent emission of one or more of α or β particles,        or γ rays. including but not limited to, iodine 131, rhenium        186, indium 111, yttrium 90, bismuth 210 and 213, actinium 225        and astatine 213; chelating agents may be used to facilitate the        association of these radio-nuclides to the high affinity TCRs,        or multimers thereof;    -   prodrugs, including but not limited to, antibody directed enzyme        pro-drugs;    -   immuno-stimulants, i.e. moieties which stimulate immune        response. Including but not limited to, cytokines such as IL-2        and IFN, Superantigens and mutants thereof, TCR-HLA fusions and        chemokines such as IL-8, platelet factor 4, melanoma growth        stimulatory protein, etc, antibodies or fragments thereof,        complement activators, xenogeneic protein domains, allogeneic        protein domains, viral/bacterial protein domains,        viral/bacterial peptides and anti-T cell determinant antibodies        (e.g. anti-CD3 or anti-CD28).        Functional Antibody Fragments and Variants

Antibody fragments and variants/analogues which are suitable for use inthe compositions and methods described herein include, but are notlimited to, the following.

Antibody Fragments

As is known to those skilled in the art, it is possible to producefragments of a given antibody which retain substantially the samebinding characteristics as those of the parent antibody. The followingprovides details of such fragments:

-   Minibodies—These constructs consist of antibodies with a truncated    Fc portion. As such they retain the complete binding domains of the    antibody from which are derived.-   Fab fragments—These comprise a single immunoglobulin light chain    covalently-linked to part of an immunoglobulin heavy chain. As such,    Fab fragments comprise a single antigen combining site. Fab    fragments are defined by the portion of an IgG that can be liberated    by treatment with papain. Such fragments are commonly produced via    recombinant DNA techniques. (Reeves et al., (2000) Lecture Notes on    Immunology (4th Edition) Published by Blackwell Science)

F(ab′)₂ fragments—These comprise both antigen combining sites and thehinge region from a single antibody. F(ab′)₂ fragments are defined bythe portion of an IgG that can be liberated by treatment with pepsin.Such fragments are commonly produced via recombinant DNA techniques.(Reeves et al., (2000) Lecture Notes on Immunology (4tth Edition)Published by Blackwell Science)

-   Fv fragments—These comprise an immunoglobulin variable heavy domain    linked to an immunoglobulin variable light domain. A number of Fv    designs have been produced. These include dsFvs, in which the    association between the two domains is enhanced by an introduced    disulfide bond. Alternatively, scFVs can be formed using a peptide    linker to bind the two domains together as a single polypeptide. Fvs    constructs containing a variable domain of a heavy or light    immunoglobulin chain associated to the variable and constant domain    of the corresponding immunoglobulin heavy or light chain have also    been produced. FV have also been multimerised to form diabodies and    triabodies (Maynard et al., (2000) Annu Rev Biomed Eng 2 339-376)-   Nanobodies™—These constructs, marketed by Ablynx (Belgium), comprise    synthetic single immunoglobulin variable heavy domain derived from a    camelid (e.g. camel or llama) antibody.-   Domain Antibodies—These constructs, marketed by Domantis (Belgium),    comprise an affinity matured single immunoglobulin variable heavy    domain or immunoglobulin variable light domain.    Antibody Variants and Analogues

The defining functional characteristic of antibodies in the context ofthe present invention is their ability to bind specifically to a targetligand. As is known to those skilled in the art it is possible toengineer such binding characteristics into a range of other proteins.Examples of antibody variants and analogues suitable for use in thecompositions and methods of the present invention include, but are notlimited to, the following.

Protein scaffold-based binding polypeptides—This family of bindingconstructs comprise mutated analogues of proteins which contain nativebinding loops. Examples include Affibodies, marketed by Affibody(Sweden), which are based on a three-helix motif derived from one of theIgG binding domains of Staphylococcus aureus Protein A. Another exampleis provided by Evibodies, marketed by EvoGenix (Australia) which arebased on the extracellular domains of CTLA-4 into which domains similarto antibody binding loops are grafted. A final example, Cytokine Trapsmarketed by Regeneron Pharmaceuticals (US), graft cytokine receptordomains into antibody scaffolds. (Nygren et al., (2000) Current Opinionin Structural biology 7 463-469) provides a review of the uses ofscaffolds for engineering novel binding sites in proteins. This reviewmentions the following proteins as sources of scaffolds: CP1 zincfinger, Tendamistat, Z domain (a protein A analogue), PST1, Coiledcoils, LACI-D1 and cytochrome b₅₆₂. Other protein scaffold studies havereported the use of Fibronectin, Green fluorescent protein (GFP) andankyrin repeats.

As is known to those skilled in the art antibodies or fragments,variants or analogues thereof can be produced which bind to variousparts of a given protein ligand. For example, anti-CD3 antibodies can beraised to any of the polypeptide chains from which this complex isformed (i.e., γ, δ, ε, ζ, and η CD3 chains) Antibodies which bind to theε CD3 chain are the preferred anti-CD3 antibodies for use in thecompositions and methods of the present invention.

Soluble TCRs or multivalent TCR complexes of the invention may be linkedto an enzyme capable of converting a prodrug to a drug. This allows theprodrug to be converted to the drug only at the site where it isrequired (i.e. targeted by the sTCR).

It is expected that the high affinity SLLMWITQC (SEQ IDNO:126)-HLA-A*0201 specific TCRs disclosed herein may be used in methodsfor the diagnosis and treatment of cancer.

For cancer treatment, the localisation in the vicinity of tumours ormetastasis would enhance the effect of toxins or immunostimulants. Forvaccine delivery, the vaccine antigen could be localised in the vicinityof antigen presenting cells, thus enhancing the efficacy of the antigen.The method can also be applied for imaging purposes.

One embodiment is provided by an isolated cell presenting a TCR of theinvention. For example, said cell may be a T cell.

Further embodiments of the invention are provided by a pharmaceuticalcomposition comprising:

-   a TCR or a multivalent TCR complex of the invention (optionally    associated with a therapeutic agent), or a plurality of cells    presenting at least one TCR of the invention, together with a    pharmaceutically acceptable carrier;

The invention also provides a method of treatment of cancer comprisingadministering to a subject suffering such cancer disease an effectiveamount of a TCR or a multivalent TCR complex of the invention(optionally associated with a therapeutic agent), or a plurality ofcells presenting at least one TCR of the invention. In a relatedembodiment the invention provides for the use of a TCR or a multivalentTCR complex of the invention (optionally associated with a therapeuticagent), or a plurality of cells presenting at least one TCR of theinvention, in the preparation of a composition for the treatment ofcancer.

Therapeutic or imaging TCRs in accordance with the invention willusually be supplied as part of a sterile, pharmaceutical compositionwhich will normally include a pharmaceutically acceptable carrier. Thispharmaceutical composition may be in any suitable form, (depending uponthe desired method of administering it to a patient). It may be providedin unit dosage form, will generally be provided in a sealed containerand may be provided as part of a kit. Such a kit would normally(although not necessarily) include instructions for use. It may includea plurality of said unit dosage forms.

The pharmaceutical composition may be adapted for administration by anyappropriate route, for example parenteral, transdermal or viainhalation, preferably a parenteral (including subcutaneous,intramuscular, or, most preferably intravenous) route. Such compositionsmay be prepared by any method known in the art of pharmacy, for exampleby admixing the active ingredient with the carrier(s) or excipient(s)under sterile conditions.

Dosages of the substances of the present invention can vary between widelimits, depending upon the disease or disorder to be treated, the ageand condition of the individual to be treated, etc. and a physician willultimately determine appropriate dosages to be used.

Additional Aspects

A scTCR or dTCR (which preferably is constituted by constant andvariable sequences corresponding to human sequences) of the presentinvention maybe provided in substantially pure form, or as a purified orisolated preparation. For example, it may be provided in a form which issubstantially free of other proteins.

The invention also provides a method of producing a high affinity TCRhaving the property of binding to SLLMWITQC (SEQ ID NO:126)-HLA-A*0201.CHARACTERISED IN THAT the TCR (i) comprises at least one TCR α chainvariable domain and/or at least one TCR β chain variable domain and (ii)has a KD for the said SLLMWITQC (SEQ ID NO:126)-HLA-A*0201 complex ofless than or equal to 1μM and/or an off-rate (kOff) for the SLLMWITQC(SEQ ID NO:126)-HLA-A* 0201 complex of 1×10⁻³ S⁻¹ or slower, wherein themethod comprises:

-   (a) the production of a TCR comprising the α and β chain variable    domains of the 1G4 TCR wherein one or both of the α and β chain    variable domains comprise a mutation(s) in one or more of the amino    acids identified in claims 7 and 8;-   (b) contacting said mutated TCR with SLLMWITQC (SEQ ID    NO:126)-HLA-A*0201 under conditions suitable to allow the binding of    the TCR to SLLMWITQC (SEQ ID NO:126)-HLA-A*0201;    and measuring the K_(D) and/or k_(off) of the interaction.

Preferred features of each aspect of the invention are as for each ofthe other aspects mutatis mutandis. The prior art documents mentionedherein are incorporated to the fullest extent permitted by law.

EXAMPLES

The invention is further described in the following examples, which donot limit the scope of the invention in any way.

Reference is made in the following to the accompanying drawings inwhich:

FIGS. 1 a and 1 b details the alpha chain variable domain amino acid andbeta chain variable domain amino acid sequences of the native 1G4 TCRrespectively.

FIGS. 2 a and 2 b show respectively the DNA sequence of soluble versionsof the native 1G4 TCR α and β chains.

FIGS. 3 a and 3 b show respectively the 1G4 TCR α and β chainextracellular amino acid sequences produced from the DNA sequences ofFIGS. 2 a and 2 b.

FIGS. 4 a and 4 b show respectively the DNA sequence of soluble versionsof the 1G4 TCR α and β chains mutated to include additional cysteineresidues to form a non-native disulphide bond. The mutated codon isindicated by shading.

FIGS. 5 a and 5 b show respectively the 1G4 TCR α and β chainextracellular amino acid sequences produced from the DNA sequences ofFIGS. 4 a and 4 b. The introduced cysteine is indicated by shading.

FIGS. 6 a-6 m detail the alpha chain variable domain amino acidsequences of the high affinity 1G4 TCR variants.

FIGS. 7 a-7 c detail the beta chain variable domain amino acid sequencesof the high affinity 1G4 TCR variants.

FIG. 8 a details the amino acid sequence of a soluble form of TRAC.

FIG. 8 b details the amino acid sequence of a soluble form of TRBC1.

FIG. 8 c details the amino acid sequence of a soluble form of TRBC2.

FIGS. 9 a-9 b detail the DNA sequence of the pEX954 plasmid.

FIGS. 10 a-10 b detail the DNA sequence of the pEX821 plasmid.

FIGS. 11 a-11 b detail the DNA sequence of the pEX202 plasmid.

FIG. 12 details the DNA sequence of the pEX205 plasmid.

FIG. 13 details further beta chain variable domain amino acid sequencesof the high affinity 1G4 TCR variants.

FIG. 14 a details the alpha chain amino acid sequences of a preferredsoluble high affinity 1G4 TCR variant.

FIG. 14 b details the beta chain amino acid sequences of a preferred(c58c61) soluble high affinity 1G4 TCR variant utilising the TRBC1constant domain.

FIG. 14 c details the beta chain amino acid sequences of a preferred(c58c61) soluble high affinity 1G4 TCR variant utilising the TRBC2constant domain.

FIG. 14 d details the beta chain amino acid sequences of a preferred(c58c61) soluble high affinity 1G4 TCR using the TRBC2 encoded constantregion fused via a peptide linker to wild-type human IL-2.

FIG. 15 a shows FACs staining of T2 cell pulsed with a range ofNY-ESO-analogue SLLMWITQV (SEQ ID NO:127) peptide concentrations usingthe high affinity c58c61 1G4 TCR-IL-2 fusion proteins.

FIG. 15 b shows FACs staining of T2 cell pulsed with a range ofNY-ESO-derived SLLMWITQC (SEQ ID NO:126) peptide concentrations usingthe high affinity c58c61 1G4 TCR-IL-2 fusion proteins.

FIG. 16 shows FACs staining of SK-MEL-37, ScaBER, J82, HcT1 19 and Colo205 cancer cells transfected with an SLLMWITQC (SEQ ID NO:126) peptideproducing ubiquitin minigene (±proteosome inhibitors) using the highaffinity c58c61 1G4 TCR-IL-2 fusion proteins.

FIG. 17 shows ELISPOT data demonstrating the ability of soluble highaffinity c58c61 1G4 TCR to inhibit CTL activation against the MEL-624cancer cell.

FIG. 18 shows ELISPOT data demonstrating the ability of soluble highaffinity c58c61 1G4 TCR to inhibit CTL activation against the SK-MEL-37cancer cell.

FIG. 19 shows inhibition of T cell activation against peptide pulsed T2cells by the soluble c58c61 high affinity 1G4 TCR as measured by IFNγproduction.

FIG. 20 shows lack of inhibition of T cell activation against peptidepulsed T2 cells by the soluble wild-type 1G4 TCR as measured by IFNγproduction.

FIG. 21 shows tumor growth inhibition caused by soluble c58c61 highaffinity 1G4 TCR-IL-2 immunoconjugates.

FIG. 22 shows the number of SLLMWITQC (SEQ ID NO:126)-HLA-A*0201antigens on the surface of Mel 526, Mel 624 and SK-Mel-37 cancer cellsas determined by fluorescent microscopy. The visualisation of cell-boundbiotinylated soluble c58c61 high affinity 1G4 TCRs was facilitated byconjugation with streptavidin-R phycoerythrin (PE).

Example 1 Production of a Soluble Disulfide-linked TCR Comprising theNative 1G4 TCR Variable Domain

RNA Isolation

Total RNA was isolated from 10000 clonal T cells by re-suspension in 100μl tri-reagent (Sigma) and processing of the lysate according to themanufacturer's instructions. After the final precipitation the RNA wasre-dissolved in 12.5 μl RNAse free water.

cDNA Production

To the above sample of RNA, 2.5/μl of 10 mM oligo-dT¹⁵ (Promega) wasadded and the sample incubated at 60° C. for 2 minutes then placed onice. Reverse transcription was carried out using OmniscriptRT kit(Qiagen) by addition of 2μ\ RT buffer (10×), 2 μl 5 mM dNTP, 1 μlOmniscript reverse transcriptase. The sample was mixed and incubated for1 hour at 37° C. cDNA was then stored at −80° C.

The above cDNA was used as template. A panel of forward primers coveringall possible alpha and beta variable chains was used to screen for, andamplify by PCR, alpha and beta chains genes. Primer sequences used forTCR chain gene amplification were designed from the NCBI website(ncbi.nlm.nih.gov/Entrez/) using accession numbers obtained from the Tcell receptor Factsbook, (2001) LeFranc and LeFranc, Academic Press,ISBN 0-12-441352-8. Alpha-chain forward primers were designed to containa ClaI restriction site and the universal alpha chain reverse primer aSail restriction site. Beta-chain forward primers were designed tocontain an AseI restriction site and universal beta reverse primer anAgeI restriction site.

Recipient vectors for the TCR gene fragments were based on a pGMT7parent plasmid, which contains the T7 promoter for high level expressionin E.coli strain BL21-DE3(pLysS) (Pan et al., Biotechniques (2000) 29(6): 1234-8).

Alpha chain purified PCR products were digested with ClaI and SalII andligated into pEX954 (see FIG. 9) cut with ClaI and XhoI.

Beta chain purified PCR products were digested with AseI and AgeI andligated into pEX821 (See FIG. 10) cut with NdeI/AgeI.

Ligation

The cut PCR product and cut vector were ligated using a rapid DNAligation kit (Roche) following the manufacturers instructions.

Ligated plasmids were transformed into competent E.coli strain XL1-bluecells and plated out on LB/agar plates containing 100 mg/ml ampicillin.Following incubation overnight at 37° C., single colonies were pickedand grown in 10 ml LB containing 100 mg/ml ampicillin overnight at 37°C. with shaking. Cloned plasmids were purified using a Miniprep kit(Qiagen) and the insert was sequenced using an automated DNA sequencer(Lark Technologies).

FIGS. 4 a and 4 b show respectively the DNA sequence of soluble versionsof the 1G4 TCR α and β chains mutated to include additional cysteineresidues to form a non-native disulphide bond.

FIGS. 5 a and 5 b show respectively the NY-ESO TCR α and β chainextracellular amino acid sequences produced from the DNA sequences ofFIGS. 4 a and 4 b

Example 2 Production of High Affinity Variants of the Soluble DisulfideLinked 1G4 TCR

The soluble disulfide-linked native 1G4 TCR produced as described inExample 1 can be used a template from which to produce the TCRs of theinvention which have an increased affinity for the SLLMWITQC (SEQ ID NO:126)-HLA-A*0201 complex.

The amino sequences of the mutated TCR alpha and beta chain variabledomains which demonstrate high affinity for the SLLMWITQC (SEQ IDNO:126)-HLA-A*0201 complex are listed in FIGS. 6 and 7 respectively (SEQID Nos: 11-83 and 84-99 respectively). As is known to those skilled inthe art the necessary codon changes required to produce these mutatedchains can be introduced into the DNA encoding these chains bysite-directed mutagenesis. (QUICKCHANGE™ Site-Directed Mutagenesis Kitfrom Stratagene).

Briefly, this is achieved by using primers that incorporate the desiredcodon change(s) and the plasmids containing the relevant 1G4 TCR chainas a template for the mutagenesis:

Mutagenesis was carried out using the following conditions: 50 ngplasmid template, 1 μl of 10 mM dNTP, 5 μl of 10× Pfu DNA polymerasebuffer as supplied by the manufacturer, 25 pmol of fwd primer, 25 pmolof rev primer, 1 μl pfu DNA polymerase in total volume 50 μl. After aninitial denaturation step of 2 mins at 95 C, the reaction was subjectedto 25 cycles of denaturation (95 C, 10 sees), annealing (55 C 10 secs),and elongation (72 C, 8 mins). The resulting product was digested withDpnl restriction enzyme to remove the template plasmid and transformedinto E. coli strain XL1 -blue. Mutagenesis was verified by sequencing.

Example 3 Production of Soluble “Zippered” High Affinity TCRs

Alpha Chain—c-jun Leucine Zipper

The construct was made by PCR stitching.

For the 5′-end of the gene the plasmid coding for the high affinity TCRalpha chains and containing the code for the introduced inter-chaindi-sulfide bridge was used as template. PCR with the following twoprimer pairs generated the desired variable domain.

5′-TRAV21 fwd (SEQ ID NO: 105) tctctcattaatgaaacaggaggtgacgcagattcctC-alpha rev (SEQ ID NO: 106) CGGCAGGGTCAGGGTTCTGG

For the 3′-end of the gene the plasmid pEX202 (see FIG. 11), coding fora wild type affinity TCR alpha chain fused to human c-jun leucine zipperdomain and not containing the code for the introduced inter-chaindi-sulfide bridge, was used as template. PCR with the following primerpair generated the desired constant domain.

C-alpha fwd (SEQ ID NO: 107) CCAGAACCCTGACCCTGCCG 3′-alpha rev(SEQ ID NO: 108) aagcttcccgggggaactttctgggctggg

The two products were mixed and diluted 1000 fold and 1 μl was used astemplate in a 50 μl PCR with 5′-TRAV21 fwd and 3′-alpha rev primers.

The resulting PCR product was digested using restriction enzymes AseIand XmaI and ligated into pEX202 cut with NdeI and XmaI.

PCRs were carried out using the following conditions: 50 pg plasmidtemplate, 1 μl of 10 mM dNTP, 5 μl of 10× Pfu DNA polymerase buffer assupplied by the manufacturer, 25 pmol of fwd primer, 25 pmol of revprimer, 1 μl Pfu DNA polymerase in total volume 50 μl. After an initialdenaturation step of 2 mins at 95 C, the reaction was subjected to 30cycles of denaturation (95 C, 10 secs), annealing (55 C 10 secs), andelongation (72C, 2 rains).

Beta Chain—c-fos Leucine Zipper

The construct was made by PCR stitching.

For the 5′-end of the gene plasmids coding for the high affinity TCRbeta chains and containing the introduced inter-chain di-sulfide bridgewere used as template. PCR with the following two primers generated thedesired variable domain gene fragment.

TRBV6-5 fwd (SEQ ID NO: 109) tctctcattaatgaatgctggtgtcactcagaccccC-beta rev (SEQ ID NO: 110) CTTCTGATGGCTCAAACACAGC

For the 3′-end of the gene the plasmid pEX205 (see FIG. 12), coding fora wild type affinity TCR beta chain fused to the human c-fos leucinezipper domain and not containing the code for the introduced inter-chaindi-sulfide bridge, was used as template. PCR with the following twoprimers generated the desired constant domain gene fragment.

C-beta fwd (SEQ ID NO: 111) GCTGTGTTTGAGCCATCAGAAG TRBC rev(SEQ ID NO: 112) aagcttcccggggtctgctctaccccaggc

The two products were mixed and diluted 1000 fold and 1 μl was used astemplate in a 50 μl PCR with TRBV6-5 fwd and TRBC rev primers. PCRs werecarried out as described above.

The resulting PCR product was digested using restriction enzymes AseIand XmaI and ligated into pEX205 cut with NdeI and XmaI.

Example 4 Expression, Refolding and Purification of Soluble TCR

The expression plasmids containing the mutated α-chain and β-chainrespectively as prepared in Examples 1, 2 or 3 were transformedseparately into E.coli strain BL21pLysS, and single ampicillin-resistantcolonies were grown at 37° C. in TYP (ampicillin 100 μg/ml) medium toOD₆₀₀ of 0.4 before inducing protein expression with 0.5 mM IPTG. Cellswere harvested three hours post-induction by centrifugation for 30minutes at 4000 rpm in a Beckman J-6B. Cell pellets were re-suspended ina buffer containing 50 mM Tris-HCI, 25% (w/v) sucrose, 1 mM NaEDTA, 0.1%(w/v) NaAzide, 10 mM DTT, pH 8.0. After an overnight freeze-thaw step,re-suspended cells were sonicated in 1 minute bursts for a total ofaround 10 minutes in a Milsonix XL2020 sonicator using a standard 12 mmdiameter probe. Inclusion body pellets were recovered by centrifugationfor 30 minutes at 13000 rpm in a Beckman J2-21 centrifuge. Threedetergent washes were then carried out to remove cell debris andmembrane components. Each time the inclusion body pellet was homogenisedin a Triton buffer (50 mM Tris-HCI, 0.5% Triton-X100, 200 mM NaCI, 10 mMNaEDTA, 0.1% (w/v) NaAzide, 2 mM DTT, pH 8.0) before being pelleted bycentrifugation for 15 minutes at 13000 rpm in a Beckman J2-21. Detergentand salt was then removed by a similar wash in the following buffer: 50mM Tris-HCl, 1 mM NaEDTA, 0.1% (w/v) NaAzide, 2 mM DTT, pH 8.0. Finally,the inclusion bodies were divided into 30 mg aliquots and frozen at −70°C. Inclusion body protein yield was quantitated by solubilising with 6Mguanidine-HCl and measurement with a Bradford dye-binding assay(PerBio).

Approximately 30 mg of TCR β chain and 60 mg of TCR α chain solubilisedinclusion bodies were thawed from frozen stocks, samples were then mixedand the mixture diluted into 15 ml of a guanidine solution (6 MGuanidine-hydrochloride, 10 mM Sodium Acetate, 10 mM EDTA), to ensurecomplete chain de-naturation. The guanidine solution containing fullyreduced and denatured TCR chains was then injected into 1 liter of thefollowing refolding buffer: 100 mM Tris pH 8.5, 400 mM L-Arginine, 2 mMEDTA, 5 mM reduced Glutathione, 0.5 mM oxidised Glutathione, 5M urea,0.2 mM PMSF. The redox couple (2-mercaptoethylamine and cystamine (tofinal concentrations of 6.6 mM and 3.7 mM, respectively) were addedapproximately 5 minutes before addition of the denatured TCR chains. Thesolution was left for 5 hrs±15 minutes. The refolded TCR was dialysed inSpectrapor 1 membrane (Spectrum; Product No. 132670) against 10 L 10 mMTris pH 8.1 at 5° C.±3° C. for 18-20 hours. After this time, thedialysis buffer was changed to fresh 10 mM Tris pH 8.1 (10 L) anddialysis was continued at 5° C.±3° C. for another 20-22 hours.

sTCR was separated from degradation products and impurities by loadingthe dialysed refold onto a POROS 50HQ anion exchange column and elutingbound protein with a gradient of 0-500 mM NaCl over 50 column volumesusing an Akta purifier (Pharmacia). Peak fractions were stored at 4° C.and analysed by Coomassie-stained SDS-PAGE before being pooled andconcentrated. Finally, the sTCR was purified and characterised using aSuperdex 200HR gel filtration column pre-equilibrated in HBS-EP buffer(10 mM HEPES pH 7.4, 150 mM NaCl, 3.5 mM EDTA, 0.05% nonidet p40). Thepeak eluting at a relative molecular weight of approximately 50 kDa waspooled and concentrated prior to characterisation by BIAcore surfaceplasmon resonance analysis.

Example 5 Biacore Surface Plasmon Resonance Characterisation of sTCRBinding to Specific pMHC

A surface plasmon resonance biosensor (Biacore 3000™) was used toanalyse the binding of a sTCR to its peptide-MHC ligand. This wasfacilitated by producing single pMHC complexes (described below) whichwere immobilised to a streptavidin-coated binding surface in asemi-oriented fashion, allowing efficient testing of the binding of asoluble T-cell receptor to up to four different pMHC (immobilised onseparate flow cells) simultaneously. Manual injection of HLA complexallows the precise level of immobilised class I molecules to bemanipulated easily.

Biotinylated class I HLA-A*0201 molecules were refolded in vitro frombacterially-expressed inclusion bodies containing the constituentsubunit proteins and synthetic peptide, followed by purification and invitro enzymatic biotinylation (O'Callaghan et al. (1999) Anal. Biochem.266: 9-15). HLA-A*0201-heavy chain was expressed with a C-terminalbiotinylation tag which replaces the transmembrane and cytoplasmicdomains of the protein in an appropriate construct. Inclusion bodyexpression levels of ˜75 mg/liter bacterial culture were obtained. TheMHC light-chain or β2-microglobulin was also expressed as inclusionbodies in E.coli from an appropriate construct, at a level of ˜500mg/liter bacterial culture.

E. coli cells were lysed and inclusion bodies are purified toapproximately 80% purity. Protein from inclusion bodies was denatured in6 M guanidine-HCl, 50 mM Tris pH 8.1, 100 mM NaCl, 10 mM DTT, 10 mMEDTA, and was refolded at a concentration of 30 mg/liter heavy chain, 30mg/liter β2m into 0.4 M L-Arginine-HCl, 100 mM Tris pH 8.1, 3.7 mMcystamine, mM cysteamine, 4 mg/ml of the SLLMWITQC peptide required tobe loaded by the HLA-A*0201 molecule, by addition of a single pulse ofdenatured protein into refold buffer at <5° C. Refolding was allowed toreach completion at 4° C. for at least 1 hour.

Buffer was exchanged by dialysis in 10 volumes of 10 mM Tris pH 8.1. Twochanges of buffer were necessary to reduce the ionic strength of thesolution sufficiently. The protein solution was then filtered through a1.5 μm cellulose acetate filter and loaded onto a POROS 50HQ anionexchange column (8 ml bed volume). Protein was eluted with a linear0-500 mM NaCl gradient. HLA-A*0201-peptide complex eluted atapproximately 250 mM NaCl, and peak fractions were collected, a cocktailof protease inhibitors (Calbiochem) was added and the fractions werechilled on ice.

Biotinylation tagged pMHC molecules were buffer exchanged into 10 mMTris pH 8.1, 5 mM NaCl using a Pharmacia fast desalting columnequilibrated in the same buffer. Immediately upon elution, theprotein-containing fractions were chilled on ice and protease inhibitorcocktail (Calbiochem) was added. Biotinylation reagents were then added:1 mM biotin, 5 mM ATP (buffered to pH 8), 7.5 mM MgCl2, and 5 μg/ml BirAenzyme (purified according to O'Callaghan et al. (1999) Anal. Biochem.266: 9-15). The mixture was then allowed to incubate at room temperatureovernight.

The biotinylated pHLA-A*0201 molecules were purified using gelfiltration chromatography. A Pharmacia Superdex 75 HR 10/30 column waspre-equilibrated with filtered PBS and 1 ml of the biotinylationreaction mixture was loaded and the column was developed with PBS at 0.5ml/min. Biotinylated pHLA-A*0201 molecules eluted as a single peak atapproximately 15 ml. Fractions containing protein were pooled, chilledon ice, and protease inhibitor cocktail was added. Protein concentrationwas determined using a Coomassie-binding assay (PerBio) and aliquots ofbiotinylated pHLA-A*0201 molecules were stored frozen at −20° C.Streptavidin was immobilised by standard amine coupling methods.

Such immobilised complexes are capable of binding both T-cell receptorsand the coreceptor CD8αα, both of which may be injected in the solublephase. Specific binding of TCR is obtained even at low concentrations(at least 40 μg/ml), implying the TCR is relatively stable. The pMHCbinding properties of sTCR are observed to be qualitatively andquantitatively similar if sTCR is used either in the soluble orimmobilised phase. This is an important control for partial activity ofsoluble species and also suggests that biotinylated pMHC complexes arebiologically as active as non-biotinylated complexes.

The interactions between 1G4 sTCR containing a novel inter-chain bondand its ligand/MHC complex or an irrelevant HLA-peptide combination, theproduction of which is described above, were analysed on a Biacore 3000™surface plasmon resonance (SPR) biosensor. SPR measures changes inrefractive index expressed in response units (RU) near a sensor surfacewithin a small flow cell, a principle that can be used to detectreceptor ligand interactions and to analyse their affinity and kineticparameters. The probe flow cells were prepared by immobilising theindividual HLA-peptide complexes in separate flow cells via bindingbetween the biotin cross linked onto β2m and streptavidin which havebeen chemically cross linked to the activated surface of the flow cells.The assay was then performed by passing sTCR over the surfaces of thedifferent flow cells at a constant flow rate, measuring the SPR responsein doing so.

To Measure Equilibrium Binding Constant

Serial dilutions of WT 1G4 sTCR were prepared and injected at constantflow rate of 5 μl min-1 over two different flow cells; one coated with˜1000 RU of specific SLLMWITQC (SEQ ID NO:126)-HLA-A*0201 complex, thesecond coated with ˜1000 RU of non-specific HLA-A2-peptide complex.Response was normalised for each concentration using the measurementfrom the control cell. Normalised data response was plotted versusconcentration of TCR sample and fitted to a hyperbola in order tocalculate the equilibrium binding constant, K_(D). (Price & Dwek,Principles and Problems in Physical Chemistry for Biochemists (2ndEdition) 1979, Clarendon Press, Oxford).

To Measure Kinetic Parameters

For high affinity TCRs K_(D) was determined by experimentally measuringthe dissociation rate constant, kd, and the association rate constant,ka. The equilibrium constant K_(D) was calculated as kd/ka. TCR wasinjected over two different cells one coated with ˜300 RU of specificHLA-A2-nyeso peptide complex, the second coated with ˜300 RU ofnon-specific HLA-A2-peptide complex. Flow rate was set at 50 μl/min.Typically 250 μl of TCR at ˜3 μM concentration was injected. Buffer wasthen flowed over until the response had returned to baseline. Kineticparameters were calculated using Biaevaluation software. Thedissociation phase was also fitted to a single exponential decayequation enabling calculation of half-life.

Results

The interaction between a soluble disulfide-linked native 1G4 TCR(consisting of the α and β TCR chains detailed in SEQ ID NOs 9 and 10respectively) and the SLLMWITQC (SEQ ID NO:126)-HLA-A*0201 complex wasanalysed using the above methods and demonstrated a K_(D) of 15 μM and ak_(off) of 1.28×10⁻¹ S⁻¹.

The TCRs specified in the following table have a K_(D) of less than orequal to 1 μM and/or a k_(off) of 1×10⁻³ S⁻1 or slower.

Alpha chain variable Beta chain variable domain sequence, domainsequence, SEQ ID NO: SEQ ID NO: 1 84 1 85 1 86 1 87 1 88 11 84 12 84 1285 12 90 11 85 11 86 11 92 11 93 13 86 14 84 14 85 15 84 15 85 16 84 1685 17 86 18 86 19 84 20 86 21 84 21 85 22 84 23 86 24 84 25 84 26 84 2784 28 84 29 84 30 84 31 84 32 84 33 84 20 86 34 86 35 89 36 89 37 89 3889 39 89 16 89 17 89 31 89 40 89 1 90 1 91 41 90 42 2 42 85 42 92 1 92 193 43 92 44 92 45 92 46 92 47 92 48 84 49 94 50 84 50 94 51 94 51 95 194 1 85 51 84 52 84 52 94 52 95 53 84 49 95 49 94 54 92 55 92 56 92 5792 58 92 59 92 60 92 61 92 62 92 63 92 64 92 65 92 66 92 67 92 68 92 6992 70 92 71 92 72 92 73 92 74 92 75 92 76 92 77 92 78 92 79 92 80 92 8192 82 92 83 92 11 96 11 97 11 98 11 99 1 89 50 117 49 117 50 118 49 11950 119 58 93 49 118 1 119 1 117 55 120 56 120 50 121 50 120 49 121 49120 48 118 53 95

Example 6 In-vitro Cell Staining using a High Affinity c58c61 NY-ESOTCR-IL-2 Fusion Protein

T2 lymphoblastoid cells were pulsed with the NY-ESO-derived SLLMWITQC(SEQ ID NO:126), NY-ESO-analogue SLLMWITQV (SEQ ID NO:127) peptide, oran irrelevant peptide at a range of concentrations (10⁻⁵-10⁻¹⁰ M) for180 minutes at 37° C. The NY-ESO-analogue SLLMWITQV (SEQ ID NO:127)peptide (V-variant peptide) was used as this peptide is known to have ahigher affinity for the binding cleft of the HLA-A*0201 complex than thenative NY-ESO-derived SLLMWITQC (SEQ ID NO:126) peptide. After pulsing,cells were washed in serum-free RPMI and 5×10⁵ cells were incubated withhigh affinity c58c61 NY-ESO TCR-IL-2 fusion protein for 10 min at roomtemperature, followed by secondary anti-IL-2 mAb conjugated with PE(Serotec) for 15 min at room temperature. After washing, bound TCR-IL-2was quantified by flow cytometry using a FACS Vantage SE (BectonDickinson). Controls, also using peptide-pulsed T2 cells were includedwhere TCR-IL-2 was omitted.

FIG. 14 a details the amino acid sequence of the alpha chain of thec58c61 NY-ESO TCR. (SEQ ID NO: 122).

FIG. 14 c (SEQ ID NO: 124) details the amino acid sequence of the betachain of the c58c61 NY-ESO TCR using the TRBC2 encoded constant region.

FIG. 14 d (SEQ ID NO: 125) details the amino acid sequence of the betachain of the c58c61 NY-ESO TCR using the TRBC2 encoded constant regionfused via a peptide linker to wild-type human IL-2.

The alpha and beta chain variable domain mutations contained within thesoluble c58c61 1 G4 TCR-IL-2 fusion protein correspond to those detailedin SEQ ID NO: 49 and SEQ ID NO: 94 respectively. Note that SEQ ID NOs:121-125 have been provided in a form which includes the N-terminalmethionine (M) and the “K” and “NA” residues omitted in the majority ofthe other TCR alpha chain and beta chain amino acid sequences.

In similar experiments SK-MEL-37, ScaBER, J82, HcT1 19 and Colo 205cancer cells transfected with a NY-ES O-derived SLLMWITQC (SEQ IDNO:126) peptide expressing ubiquitin minigene construct were used. Thecancer cells were transfected using substantially the methods describedin (Rimoldi et al, (2000) J. Immunol. 165 7253-7261). Cells werelabelled as described above.

Results

FIG. 15 a shows FACs staining of T2 cell pulsed with a range ofNY-ESO-analogue SLLMWITQV (SEQ ID NO:127) peptide concentrations usingthe high affinity c58c61 1 G4 TCR-IL-2 fusion proteins. FIG. 15 a showsFACs staining of T2 cell pulsed with a range of NY-ESO-analogueSLLMWITQV (SEQ ID NO:127) peptide concentrations using the high affinityc58c61 1G4 TCR-IL-2 fusion proteins.

FIG. 15 b shows FACs staining of T2 cell pulsed with a range ofNY-ESO-derived SLLMWITQC (SEQ ID NO:126) peptide concentrations usingthe high affinity c58c61 1G4 TCR-IL-2 fusion proteins.

FIG. 16 shows FACs staining of SK-MEL-37, ScaBER, J82, HcT1 19 and Colo205 cancer cells transfected with an SLLMWITQC (SEQ ID NO:126) peptideproducing ubiquitin minigene (±proteosome inhibitors) using the highaffinity c58c61 1G4 TCR-IL-2 fusion proteins.

Example 9 CTL Activation ELISPOT Assay

The following assay was carried out to demonstrate that the soluble highaffinity c58c61 NY-ESO TCR was capable of inhibiting activation of anSLLMWITQC (SEQ ID NO:126)-HLA-A*0201 specific CTL clone (1G4). IFN-γproduction was used as the read-out for CTL activation.

Reagents

R1O Assay media: 10% FCS (heat-inactivated, Gibco, cat# 10108-165), 88%RPMI 1640 (Gibco, cat# 42401-018), 1% glutamine (Gibco, cat# 25030-024)and 1% penicillin/streptomycin (Gibco, cat# 15070-063).

Peptide: (obtained from various sources) initially dissolved in DMSO(Sigma, cat# D2650) at 4 mg/ml and frozen.

Wash buffer: 0.01M PBS/0.05% Tween 20 (1 sachet of Phosphate bufferedsaline with Tween 20, pH7.4 from Sigma, Cat. # P-3563 dissolved in 1liter distilled water gives final composition 0.01M PBS, 0.138M NaCl,0.0027M KCl, 0.05% Tween 20). PBS (Gibco, cat#10010-015).

The EliSpot kit contains all other reagents required i.e. capture anddetection antibodies, skimmed milk powder, BSA, streptavidin-alkalinephosphatase, BCIP/NBT solution (Human IFN-g PVDF Eli-spot 20×96 wellswith plates (IDS cat# DC-856.051.020, DC-856.000.000). The followingmethod is based on the instructions supplied with each kit but containssome alterations.

MEL-624 and SK-MEL-37 melanoma cell lines were treated with trypsin for5 minutes at 37° C. The cells are then washed and re-suspended in R10media.

50000 target cells were then plated out per well in 50 μl of R10 mediain a 96 well ELISPOT plate (Diaclone).

The following was then added to the above target cell cultures:

-   1×10⁻⁷ M high affinity c58c61 TCR, or an irrelevant TCR, in 50 μl of    R10 media.-   600 SLLMWITQC (SEQ ID NO:126)-HLA-A*0201 specific T cells (clone    1G4) in 50 μl of R10 media.

These cultures were then incubated for 24 hours at 37° C., 5% CO₂. TheELISPOT plates were processed according to the manufacturersinstructions.

Results

The soluble high affinity c58c61 1G4 TCR strongly inhibited theactivation of 1G4 T cell clones against the melanoma cells, as measuredby IFN-γ production. Whereas the irrelevant high affinity TCR had noinhibitory effect. (See FIG. 17 for MEL-624 cancer cell line results andFIG. 18 for SK-MEL-37 cancer cell line results).

Example 10 CTL Activation ELISA Assay

The following assay was carried out to demonstrate that the soluble highaffinity c58c61 1G4 TCR was capable of inhibiting activation of anSLLMWITQC (SEQ ID NO:126)-HLA-A*0201 specific CTL clone (1G4). EFN-γproduction was used as the read-out for CTL activation.

Reagents

R10 Assay media: 10% FCS (heat-inactivated, Gibco, cat# 10108-165), 88%RPMI 1640 (Gibco, cat# 42401-018), 1% glutamine (Gibco, cat# 25030-024)and 1% penicillin/streptomycin (Gibco, cat# 15070-063).

Peptide: (obtained from various sources) initially dissolved in DMSO(Sigma, cat# D2650) at 4 mg/ml and frozen.

Wash buffer: 0.01M PBS/0.05% Tween 20 (1 sachet of Phosphate bufferedsaline with Tween 20, pH7.4 from Sigma, Cat. # P-3563 dissolved in 1liter distilled water gives final composition 0.01M PBS, 0.138M NaCl,0.0027M KCl, 0.05% Tween 20). PBS (Gibco, cat#10010-015).

The ELISA kit contains all other reagents except BSA (Sigma), requiredi.e. capture and detection antibodies, skimmed milk powder,streptavidin-HRP, TMB solution (Human IFN-g Eli-pair 20×96 wells withplates. The following method is based substantially on the instructionssupplied with each kit.

Method

ELISA plates were prepared according to the manufacturers instructions.(Diaclone kit, Immunodiagnostic systems, UK. T2 cell line target cellswere washed and re-suspended in R1O media with or without varyingconcentrations (100 nM-10 pM) of SLLMWITQC (SEQ ID NO:126) peptide, thenincubated for 1 hour at 37° C., 5% CO₂.

10,000 target cells per well were then plated out into a 96 well ELISAplate.

To these plates the following was added to the relevant well:

-   1×10⁻⁶ M to 3×10⁻¹² M of the high affinity c58c61 1 G4 TCR or    wild-type 1 G4 TCR in 50 μl of R10 media.-   5000 1G4 effector cells in 50 μl of R10 media.

The plates were then incubated for 48 hours at 37° C., 5% CO₂. The ELISAwas then processed according to manufacturer's instructions.

Results

The soluble high affinity c58c61 1 G4 TCR strongly inhibited theactivation of 1 G4 T cell clones against the peptide-pulsed targetcells, as measured by IFN-γ production. Whereas the wild-type 1G4 TCRhad no inhibitory effect. (See FIG. 19 for the high affinity c58c61 1G4TCR and FIG. 20 for the wild-type 1G4 TCR).

Example 11 In-vivo Tumour Targeting using a High Affinity c58c61 IG4TCR-IL-2 Fusion Protein

This work was carried out to investigate the ability of a high affinityc58c61 1G4 TCR-IL-2 fusion protein described in Example 6, to inhibitgrowth of human tumor cells engrafted in nude mice.

Fifty female nude mice (HARLAN, France) were used in this trial.

All animals were injected subcutaneously with the human melanomatumour-forming cell line (SK-MEL-37) which had been stably transfectedwith a NY-ESO peptide/ubiquitin minigene construct in ensure enhancedexpression of the appropriate class I-peptide target at the cellsurface. Tumors were allowed to grow in the animals for 5 days to allowtumour development prior to commencement of treatment.

The rats then received the following i.v. bolus dosage of c58c61 highaffinity NY-ESO TCR/IL-2 fusion protein:

-   Doses ranged between 0.02 and 1.0 mg/kg high affinity 1G4 TCR/IL-2    fusion proteins in PBS, administered at 5, 6, 7, 8, 11, 13, 17, 20,    24, 28, and 30 day post-tumor engraftment. In all experiments, a    control treatment group was included where PBS alone was substituted    for the TCR/IL-2 immunoconjugate.

Tumor size was then measured using callipers and tumor volume determinedaccording to the following formula (W²×L)/2, where W=the smallestdiameter of the tumor, and L=is the longest diameter.

Results

The therapeutic effect of the TCR/IL-2 immunoconjugates in terms oftumor growth inhibition is shown in FIG. 21.

Conclusions

The TCR/IL-2 immunoconjugate exhibited a clear dose-dependent anti-tumoreffect as shown by the tumour growth curves depicted in FIG. 21.

Example 12 Quantification of Cell Surface TCR Ligands by FluorescenceMicroscopy using High Affinity c58c61 1G4 TCR

The number of SLLMWITQC (SEQ ID NO:126)-HLA-A*0201 antigens on cancercells (Mel 526, Mel 624 and SK-Mel-37 cell lines) was determined (on theassumption that one fluorescence signal relates to a single labelled TCRbound to its cognate pMHC ligand on the surface of the target cell) bysingle molecule fluorescence microscopy using the high-affinity c58c611G4 TCR. This was facilitated by using biotinylated TCR to target theantigen-expressing cancer cells and subsequent labelling of cell-boundTCR by streptavidin-R phycoerythrin (PE) conjugates. Individual PEmolecules were then imaged by 3-dimensional fluorescence microscopy.

Staining of adherent cells. The cancer cells were plated into chamberwell slides and allowed to adhere overnight in incubator. (37° C., 5%CO₂) Media was removed and replaced with fresh R10. Media was removed,and cells washed twice with 500 μl of PBS supplemented with 400 nM MgCl₂(PBS/Mg). Cells were incubated in 200 μl of TCR solution (5 μg ml⁻¹ highaffinity c58c61 1G4 TCR, or 5 μg ml⁻¹ of an “irrelevant” HLA-A2-taxpeptide-specific high affinity TCR, in PBS/Mg containing 0.5% BSAalbumin) for 30 min at 4° C. TCR solution was removed, and cells werewashed three times with 500 μl of PBS/Mg. Cells were incubated in 200 μlof streptavidin-PE solution (5 μg ml⁻¹ streptavidin-PE in PBS/Mgcontaining 0.5% BSA) at room temperature in the dark for 20 min.Streptavidin-PE solution was removed and cells were washed five timeswith 500 μl of PBS/Mg. Wash media was removed, and cells kept in 400 μlof imaging media before imaging by fluorescence microscopy.

Fluorescence microscopy. Fluorescent microscopy was carried out using anAxiovert 200M (Zeiss) microscope with a 63× Oil objective (Zeiss). ALambda LS light source containing a 300W Xenon Arc lamp (Sutter) wasused for illumination, and light intensity was reduced to optimal levelsby placing a 0.3 and a 0.6 neutral density filter into the light path.Excitation and emission spectra were separated using a TRITC/Dil filterset (Chroma). Cells were imaged in three dimensions by z-stackacquisition (21 planes, 1 μm apart). Image acquisition and analysis wasperformed using Metamorph software (Universal Imaging) as described(Irvine et al, Nature (419), p845-9, and Purbhoo et al, NatureImmunology (5), p524-30.).

Results

As demonstrated by FIG. 22 the above method was used successfully toimage high affinity 1G4 TCR bound to SLLMWITQC (SEQ IDNO:126)-HLA-A*0201 antigens on the surface of Mel 526, Mel 624 andSK-Mel-37 cancer cells.

1. An isolated cell having a TCR have the α chain extracellular sequenceSEQ ID NO:5 and the β chain extracellular sequence SEQ ID NO:6 exceptthat amino acids 95T and 96S of SEQ ID NO:5 are replaced by 95L and 96Y.2. An isolated cell having a TCR have the α chain extracellular sequenceSEQ ID NO:5 and the β chain extracellular sequence SEQ ID NO:6 exceptthat amino acids 95T and 96S of SEQ ID NO:5 are replaced by 95L and 96Yand amino acid T162 of the α chain and amino acid S169 of the β chainare replaced by 162C and 169C and comprising a disulfide bond between achain 162C and β chain 169C, using the numbering of SEQ ID NOS:5 and 6.3. A pharmaceutical composition comprising: a plurality of cells havingthe TCR of claim 1; and a pharmaceutically acceptable carrier.
 4. Apharmaceutical composition comprising: a plurality of cells presentinghaving the TCR of claim 2; and a pharmaceutically acceptable carrier.